1. Field of Invention
The present invention relates to a connection apparatus and particularly to a connection apparatus and a portable system (such as a satellite navigation device) adopted in the connection apparatus that are used in wireless navigation systems to enable a traffic message channel (TMC) device, to be linked to the satellite navigation device through a universal serial bus (USB).
2. Related Art
Development of the information society has created a higher demand for traffic information. To establish a comprehensive traffic information announcement system is the main content of an intelligent traffic system. This is a traffic information service, heavily focused on city traffic management in many countries.
In most cities and metropolitan areas of many countries traffic broadcasting radio stations have been set up. Before the advanced vehicle-based navigation devices are widely available, the traffic broadcasting radio station is the main channel for announcing instant and dynamic traffic information. Most foreign traffic information broadcastings adopt the radio digital system (RDS) developed by the European Broadcasting Union (EBU). The present RDS has been converged with the TMC to form RDS-TMC. According to statistics, information utilization that adopts the RDS-TMC has increased from 39% of the regular traffic broadcasting system to 64%, travel time can reduce 3%-9%, and driving speed can increase 30%. In recent years, with the advance of traffic broadcasting technology, the broadcasting method has switched from analog to digital. With the new generation of handheld satellite navigation devices coupled with the TMC system, users have even better control of traffic conditions.
However, problems still exist for coupling the USB 1.1 interface with the TMC device and satellite navigation device. For instance, power supply is one of the problems. As the general satellite navigation device is connected to other electronic devices (such as computers) through the USB interface, the voltage required for the satellite navigation device is provided from the computer. On the other hand, when coupling with the TMC device, the voltage required for the TMC device has to be provided by the satellite navigation device.
Hence how to smoothly connect the TMC device to the satellite navigation system through the USB is an issue remained to be resolved in the industry.